The ecm controls the engine fan. That's why you have no ground . Is your truck equipped with a A/C? If yes, you should check the high pressure switch; if it's defect , the fan will stay on. Locate the switch, betwwen the a/c compressor and the expansion valve, unplug it and jump the two terminals. If it was the problem the fan should go off. You can replace it without emptying the system. Other wise, what does your coolant temperature gauge reads?? do you have a check engine light on?? You said you replkaced the solenoid on the back of the tranny??? I'm not familiar with volvos but the solenoids for the engine fan are located on or near the firewall... Let me know.